In applications such as adhesives, exterior coating materials, bard coats, and antireflection films, investigations are being made on techniques in which organic materials/inorganic materials are compounded to thereby improve marring resistance, cured-object strength, adhesion to contacting materials, etc. Of these, with respect to combinations with an organic material of the polymerization curing type, attention is focused on alkoxysilanes having a polymerizable group and/or products of the hydrolysis and condensation thereof. For example, JP-A-9-169847 proposes use of a combination of a specific polyalkoxypolysiloxane and a polymerizable silane coupling agent. However, the reaction between the polyalkoxypolysiloxane and the polymerizable silane coupling agent is difficult to conduct sufficiently, resulting in a low content of polymerizable groups introduced. Because of this, the cured object obtained is insufficient in marring resistance and strength. In JP-A-9-40909 is reported a product of the partial co-hydrolysis/condensation of an alkoxysilane containing an organic functional group and a tetraalkoxysilane. However, the liquid has insufficient storability.
On the other hand, the antireflection films used in displays such as cathode ray tube displays (CRTs), plasma displays (PDPs), electroluminescent displays (ELDs), and liquid-crystal displays (LCDs) are disposed generally on the outermost surface of the display so as to reduce reflectance on the principle of optical interference in order to prevent the contrast decrease and image reflection in the display which are attributable to the reflection of external light.
Such an antireflection film can be produced by forming a high-refractive-index layer on a substrate and further forming thereon a low-refractive-index layer having an appropriate thickness. In order for a low-refractive-index layer to realize a low reflectance, it is desirable that the layer be made of a material having a refractive index as low as possible. Furthermore, since the antireflection film is disposed on the outermost surface of a display, it is required to have high marring resistance. In order for a thin film having a thickness of around 100 nm to have high marring resistance, the strength of the film itself and adhesion to the underlying layer are necessary.
Techniques for reducing the refractive index of a material include (1) to incorporate fluorine atoms and (2) to reduce the density (to incorporate voids). However, these techniques each impair film strength and adhesion and this tends to result in a decrease in marring resistance. To reconcile a low refractive index with high marring resistance has been a subject difficult to accomplish.
For example, JP-A-11-189621, JP-A-11-228631 and JP-A-2000-313709 describe a technique in which a polysiloxane structure is incorporated into a fluoropolymer to reduce the coefficient of friction of the coating film surface and thereby improve marring resistance. This technique is effective in some degree in improving marring resistance. However, even when this technique alone is applied to coating films intrinsically deficient in coating film strength and interfacial adhesion, sufficient marring resistance is not obtained.
One technique for heightening coating film strength is to incorporate an inorganic filler into a low-refractive-index layer. By using fine inorganic particles having a low refractive index as a filler, coating film strength can be heightened without increasing the refractive index of the layer itself. However, it is difficult to improve adhesion to the underlying layer by the incorporation of an inorganic filler, and marring resistance is still insufficient.